Abrading apparatus



y 1941- G. B. LIINDERQMAN, JR I 2,247,391

ABRADING APPARATUS Filed Dec. 22, 1937 7 Sheets-Shet 1 Garrett B. Linderman, fr:

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y 1941- G. B. LINDERMAN, JR 7,39

ABRADING APPARATUS A '7 Sheets-Sheet 3 Filed Dec. 22, 1937 Qwuwvtom 9543 MM f%%rm I W y 1941- G. B. LINDERMAN, JR 2,247,391

ABRADING APPARATUS Filed Dec. 22, 1937 '7 Sheets-Sheet 4 3mm Gar/weir 5. L/hdenwcm Jr.

JMs /VW y 1941- e. B. LINDEIRMAN, JR 7,391

ABRADING APPARATUS Filed Dec. 22, 1957 7 Sheets-Sheet 6 5 MM BMW July 1', 1941.

G. B. LINDERMAN, JR

ABRADING APPARATUS Filed Dec. 22, 1937 7 Sheets-Sheet 7 glwua/rvbon Garr'ell Lina ermam 'r.

Patented July 1, 1941 ABRADING APPARATUS Garrett B. Linderman, Jr., Hagerstown, Md, as-

signor to Pangborn Corporation, Hagerstown, Md, a corporation of Maryland Applicatien December 22, 1937, Serial No. 181,241

32 Claims.

The present invention relates to abrading apparatus, and more particularly to apparatus known in the trade as blast-cleaning machines embodying mean for projecting a stream of abrasive in the form of sand or steel abrasive against castings or other articles of work to be cleaned of surface accumulations.

Although centrifugal abrading machines have been known for years in the abrading art, both with directional control and without directional control, the problem of wear of the blades and other parts has been a seriou consideration, regardless of whether they are of the slider type, wherein the abrasive is admitted at low velocity over the inner ends of the blades and is continuously accelerated to the blade tips or whether they are wheels embodying batter blades where the entire abrading velocity is imparted to the abrasive by a single instantaneous impact therewith.

Although the slider type machines in commercial use today represent a great advance in the art over the machines heretofore in use they do not possess all of the operating characteristics desired and fall considerably short of the ideal machine which would pick the abrasive up without shock and gradually move it out to the periphery of the rotor without sliding it and then discharge it without wearing influence upon any part of the machine.

In the co-pending application of Waiter L. Keefer, Serial No. 162,214, filed September 2, 1937, now Patent No. 2,116,153, dated May 3, 1938, there is disclosed an abrading machine which is quite a departure from the machines heretofore proposed and it also differs from the slider type commercial machines now in use as it does not pick-up the abrasive with abrasive propelling blades but employs a deflector for dislodging abrasive from the rim of a rotor operating at high speed.

The present invention relates to abrading machines embodying certain basic principles of those disclosed in the aforementioned Keefer patent and the major object thereof is to generally improve and refine the construction and operation of those machines and to provide machines possessing further highly desirable characteristics and advantages over the machines heretofore proposed.

It is another object to so relate the abrasive dislodging disc of an abrasive propelling rotor that the most efficient results are secured.

A further object of the invention is to provide an abrading machine having a rotor adapted to centrifugally retain abrasive on an inwardly facing surface with a rotatable disc for dislodging abrasive from the rim, the axis of the disc being so inclined and offset with respect to the axis of the rotor as to efficiently discharge the abrasive and produce minimum abrasion of the disc.

The invention also aims to provide an abrading machine having an inwardly facing abrasive retaining surface rotatable at high speed and a rotatable disc for dislodging the abrasive from the rim and discharging it therefrom at an abrading velocity, the axis of rotation of the disc being inclined to the axis of rotation of the rim and also oifset forwardly with respect to the direction of rotation of the rim, to effect an efiicient discharge of abrasive from the rim.

It is a further object to devise. an abrasive propelling rotor of hollow construction and having an abrasive retaining surface from which it is adapted to be dislodged by a disc or the like, the parts being so designed as to maintain the rotor full of abrasive so as to insure static and dynamic balance of the machine during operation.

A further object is to provide an abrasive propelling rotor with a peripherally located abrasive-acceleration groove, and to provide stationarily supported means for depositing abrasive directly in the groove while the rotor is in operation, thereby allowing the abrasive to be directly picked up by the body of abrasive in the groove, without contacting machine parts.

Another object is to provide a rotatable disc assembly for dislodging the abrasive from the rim of an abrasive throwing rotor which is adjustably supported so that the inclination and also the degree of offset of the axis of the disc, with respect to the axis of the rotor, may be varied at will so as to vary the operating characteristics of the machine as may be desired.

Another object is to provide an abrasive dislodging disc having further important adjusting features for varying at will the location of the disc with respect to the rotor.

A further object is to provide a rotor having a web providing a flange structure defining an abrasive pick-up zone and an abrasive retaining zone from which the abrasive is adapted to be dislodged at a predetermined point in the rotation of the rotor, the twozones being disposed side-by-side and having means between them for controlling abrasive flow therebetween.

Still another object is to provide an abrading rotor having a rim from which the abrasive is dislodged by a disc or the like, with special forms of discharge edge constructions over which the abrasive is discharged and which are designed to impart various actions upon the abrasive, depending upon the discharge stream characteristics desired in the particular installation involved.

Another object is to provide a novel apparatus which makes use of a phenomenon discovered by me and which makes it possible to discharge the abrasive from the rim of the rotor with the expenditure of a minimum of energy.

My invention also aims to provide separate removable and replaceable wear elements to take the wear of the abrasive at critical points and to provide novel structures for proteotin certain parts of the machine against abrasion.

Further objects of the invention will become apparent as the specification proceeds in connection with the annexed drawings, and from the appended claims. In the drawings:

Figure 1 is a longitudinal sectional view through one form of abrasive throwing wheel embodying the invention, and in order to simplify the disclosure certain parts are diagrammatically illustrated.

Figure 2 is an end elevation of the wheel shown in Figure 1 and illustrates the parts as they appearwith the feed spout removed, and viewed from the right-hand side of Figure I.

Figure 3 is a longitudinal section through the rotor shown in Figure 1 taken along line 3-3 of Figure 4 and illustrates details of the construction not shown in that figure;

Figure 4 is a fragmental face View of the rotor shown in Figure 8 and illustrates the parts as they appear when the feed cone and face plate have been removed from the rotor.

Figure 5 is a longitudinal sectional view through the machine illustrated in Figures 1 to 4, inclusive, and it has been taken through the rotor looking verticallyupwardly along a ver' tical plane containing the axis of the rotor so as to illustrate the manner in which the takeoiT disc cooperates with the abrasive.

Figure 6 is a view somewhat similar to Figure 5, but it has been taken at an angle to the vertical so as to view the parts along a plane containing the axis of the take-oil disc and the point of contact of the disc with the abrasive.

Figure 7 is a perspective View illustrating the front of a rotor of modified construction also embodying the invention, and this view also illustrates one of the wear plates used in the rotor as it appears when removed from the machine.

Figure 8 is a rear perspective view of the rotor of Figure 7 showing the manner in which the view illustrating the periphery of the rotor web and flange structure of the rotor shown in Figure 7.

Figure 15 is a view somewhat similar to Figure 14, but the section is taken substantially along line 55-45 of Figure 7, so as to illustrate one of the openings in the wear plate.

Figure 16 is a fragmental sectional view taken transversely through the take off discs and illustrates the manner in which they cooperate with the abrasive on the rim of the rotor.

Figure 17 is a fragmental side elevational View of a modified form of ring constituting a discharge edge over which the abrasive passes after it leaves the rim of the wheel.

Figure 18 is an enlarged sectional view taken .along the line i8| 8 of Figure 17.

Figure 19 is a fragmental transverse sectional view'through a'modified form of ring embodying blades, and is adapted to be used with the machine shown in Figurel i.

Figure 20 is an end elevational view of the structure shown in Figure 19.

Figure "21 is a fragmental sectional View on an enlarged scale of the rotor of Figure '14 as it appears when equipped with a deflector ring assembly, also forming pa'rtof the invention.

Figure 22 is a fragmental longitudinal sectional View of a further modified'fori'n of wheel forming part of the invention.

Figure 23 is a fragmental end elevational view of the structure shown in Figure 22 as it appears when viewed from the right-hand side of that figure.

Figure 24 is a fragmental sectional view showing a modified form of abrasive flow control ring for use in the apparatus shown in Figure 22; and

Figure 25 is a fragmental end elevational view' of the structure shown in Figure 24ers it appears when viewed from the right-hand side of that several views thereof, and with particular reference to Figures 1 and 2, in which the apparafeed spout cooperates with the abrasive acceleration groove of the rotor.

Figure 9 is a perspective view of the bearing assembly for the disc and shows the manner in which it is supported on the housing.

Figure 10 is a perspective view of the take-oil disc assembly and related parts employed in the form of invention illustrated in Figures '7, 8'

and 9.

Figure 11 is a vertical sectional view through the housing and bed plates for supporting the take-off disc and shows the bearing assembly in elevation.

Figure 12 is a view looking down upon the take-oil" disc bearing assembly, and one-half of the structure is shown in section to more clearly illustrate the details thereof.

Figure 13 is a rear View oithe bearing assembly and its mounting plate.

Figure 14 is an enlarged iragmental sectional tus is somewhat diagrammatically illustrated, a rotatable shaft A carries a rotor B having a web portion and a flange, and a plate Ccoor'ierates with the rotor to provide a central abrasive inlet and a plurality of passages for feeding the abrasive outwardly to the flange. A feed spout D is employed to feed abrasive into the wheelby gravity and a circular disc E, which will be hereinafter referred to as a take-off disc, is mounted for rotation on a shaft independently of rotor B and is operablefto dislodge the abrasive from the rotor rim at a predetermined point in the rotation of the rotor. structure F encloses the lower end of the 'feed spout and the feed cone of the rotor for carrying back into the abrasive reclamation system any abrasive which fails to properly enter the center of the wheel.

As seen in Figure 2, the axis of disc E is displaced forwardly with respect to the direction of rotation of the rotor a distance S. It is also observed in Figure'l that the planeof disc E appears to be substantially normal to the-surface I of the abrasive lying on the rotor flange. The relationship of the axis of the disc E with respect to the rotor will be taken up in detailhereinafter. i

By properly positioning the angular point of contact ofdisc E with the abrasive'lying' onthe A hopper or chute flange of the rotor the apparatus may be made to discharge in any desired direction. With the disc located as shown in Figure 2, the discharge of abrasive from the wheel is found to take place as indicated at G at between the nine and ten oclock position, and it occurs substantially tangentially as shown.

One detailed form which the rotor construction may assume is shown in Figures 3 and 4, and

with continued reference to these figures, rotor 1 B is secured to the enlarged end It of a shaft by means of a plurality of cap screws l l. The front face of the rotor is provided with a plurality of preferably diamond-shaped bosses it so as to define a plurality of outwardly flaring lands or grooves E3 on the face of the rotor. A coneshaped feeding member i l and a circular plate it are secured to the rotor by means of a plurality of cap screws i6 and ll, which hold plate it in clamping engagement with the tops of bosses l2. Member it cooperates with feed spout D as shown in Figure 1 and is operative to feed the abrasive into the passages defined by grooves 13 and plate I5.

The rim of the rotor is provided with a cylindrical surface l3 and a recessed cylindrical surface I9 having a peripheral groove 2% formed therein. A resilient ring 22, which assumes the form of a split metal band, is provided with a plurality of rivets or like projections 23, and it is sprung into place in the rotor against surface ill with rivets 23 seating in groove 2!. When the parts are in assembled position, the ends of the ring 32 are disposed in closely abutting relation as indicated at 2% and projections 23 prevent the ring 22 from being axially displaced with respect to the rotor. A curved surface 25 is provided where surface l8 merges into the web of the rotor and the outer edge of plate ltl is disposed closely adjacent surface l8 and is provided with a plurality of slots 2'! having beveled inner ends 28,

Accordingly, with the rotor rotating at normal operating speed, preferably in the neighborhood of 2400 to 2509 R. P. M., when abrasive issues from spout D into member is, it slides centrifugally over the inclined surface of the latter and finds its way into the outwardly extending passages. The abrasive then contacts curved surface 25 and is directed laterally through slots 2? in plate I? and on to surface it and the inner surface of ring 22.

It has been found that the abrasive builds up on the flange at a predetermined angle of repose and then no more abrasive will pass through openings 2f unless disc E is in operative position. This angle has been designated in Figure 3 as angle X. The angle of repose will vary, depending upon the speed of the Wheel and the nature of the abrasive. It has been found that with a speed of 2450 R. P. M. the angle of repose is approximately 27 when number 40 steel grit is used. At higher speeds the abrasive flattens out and decreases the angle of repose, but for the present purposes, the angle of 27 may be taken as the proper angle under practical operating conditions.

Slots 2l are preferably so dimensioned that when the wheel is operating up to speed and no abrasive is being dislodged from the rim by disc E, the layer of abrasive, built up to its angle of repose, will act as a barrier against the passage of further abrasive, thereby maintaining the wheel full of abrasive and if spout D happens to be supplying the Wheel with abrasive at this time,

the excess abrasive will merely be by-passed through hopper F back into the abrasive system. Therefore, no discharge of abrasive from the wheel will occur unless disc E is actually in oplodge the abrasive.

Therefore, with the wheel rotating and being supplied with abrasive, a minute pile of abrasive will lie on the abrasive-supporting surface opposite each slot 2'l in plate 55 and they are sufficiently numerous so that the piles of abrasive are comparatively close together. As a matter of fact, if desired, plate l5 itself may terminate short of surface ill so that the abrasive will lie in a continuous conical pile upon the flange if desired. The inner edge 23 of opening 21 is preferably so designed as to predetermine the height of the layer and thereby insure that when the abrasive has built-up to its angle of repose the right-hand end of the layer will terminate short of the discharge edge.

It is also apparent that with the wheel rotating at operative speed, with abrasive being supplied through spout D, it is picked up with practically no impact whatever because the incoming abrasive contacts other abrasive closely adjacent the axis of rotation, and as it slides outwardly in grooves l3 it is gradually accelerated and when it is discharged onto the abrasive-supporting surfaces 58 and 22 it is rotating exactly at the speed of the rotor. Also, as soon as any quantity of abrasive is removed from the abrasive-supporting surface by disc E, abrasive promptly flows through slots 2'! and automatically replenishes the abrasive discharged.

In dislodging or deflecting the abrasive from the rim of the rotor I make use of a phenomenon which enables the disc to effect discharge of the abrasive with a minimum of wear and in describing this phenomenon it will be helpful to point out that with a particle on an inclined plane, if inclination is slightly less than the angle of repose, the particle will not slide down the slope. However, if the particle is projected along the face of the plane, parallel to the upper horizontal edge, it will slide down the slope as long as it has any horizontal velocity. The particle will come to rest after taking a course describing a generally curved trajectory, and if it is again given a horizontal velocity it will again slide down the plane and if this process is repeated enough times it will eventually slide off the plane. l his shows that as long as horizontal velocity can be supplied the particle will continu to slide down the slope. The wheel of this invention utilizes this principle, but it involves a rotating cone rather than an inclined plane, and furthermore the horizontal velocity is initiated by the take-off disc, and having once been initiated is automatically and continuously supplied by the inherent characteristics of the cone formed by the abrasive surface until it leaves the wheel.

For instance, with reference to Figure 3, assuming that the particle in question is lying on the surface of the layer of abrasive, and the surface of the abrasive is disposed at an angle just equal to the angle of repose, only a small force need be supplied to the particle by the take-off disc in order to start it moving down the inclined plane defined by the upper surface of the pile of abrasive.

I have discovered that once the abrasive is contacted by the take-off disc the particles will roll down the cone and will actually gain in velocity until it leaves the cone, thereby differing basically from the previous illustration of an inclined plane. This is explained by the fact that the surface velocity of the cone increases as the particle moves outwardly thereover (because of the increasing radius) with the result that the relative velocity between the cone and the particle is still higher, thereby causing the particle to continue to move and accelerate, whereas in the simple inclined plane example previously described the particle would come to rest after having been displaced a predetermined distance.

' From the foregoing it is apparent that in order to cause the abrasive to discharge from the rim of the wheel, it is only necessary to set up a difference of velocity between a particular particle of abrasive and the surface defined by the pile of abrasive on the rotor rim. This can be effected by mounting the disc E with its axis lying in the same plane as the axis of the rotor, and applying a slight braking force upon it, so that the pressure of the disc sliding on the abrasive causes u some of the abrasive to be decelerated to some speed between its own speed and the full peripheral speed of the wheel. For instance, a relative speed of three feet per second has been found sufiicient to cause the abrasive to slide down the slope of the cone and be discharged by the wheel. However, in order to do away with the necessity for a braking mechanism and resulting frictional losses, I preferably mount the disc with its axis inclined and offset with respect to the axis of the rotor so as to set up the required difference in velocity of the abrasive and the wheel by a scraping or dislodging action. In Figures 5 and 6 I have fully disclosed one of the positions the disc may assume to efficiently discharge the abrasive.

First, referring to Figures 1 and 2, it will be observed that disc E is so mounted as to dispose its plane substantially normal to the plane of the surface of the abrasive on the rim. In other words, its axis is disposed at an angle Y with respect to the axis of shaft A, and which has been shown as being equal to angle X, the angle of repose of the abrasive. I have found that angle Y for best results may be greater but should not be less than the angle of repose of the abrasive on the rim. Therefore, if the angle of repose X is equal to 27, angle Y should preferably be 27 or greater in order to effect efiicient discharge of the abrasive;

Referring to Figure 5, which is a view looking vertically upward along a plane containing the axis of rotation 3! of the rotor, disc E is observed to be inclined but its axis 32 is nevertheless contained in a vertical plane parallel to a vertical plane containing axis 3! and spaced therefrom by a distance S. I have also found it preferable that the axis 32 of disc E be displaced forwardly with respect to the direction of therotation of the rim from a parallel plane containing the axis of the rotor in order to dislodge the abrasive from the rim. If the disc axis is displaced rearwardly, the disc will effect a difference in velocity but it will interfere with the proper discharge of the abrasive because it will tend to push the abrasive upthe inclined conical layer rather than downwardly, as is efiected by a disc whose axis is displaced forwardly. The magnitude of S determines the scraping action that will be exerted upon the abrasive and hence influences the capacity of the wheel, as will hereinafter appear.

Disc E, due to the fact that it is displaced a distance S from the rotor axis 3!, does not contact the abrasive along a horizontal plane containing the axis but contacts it at the point indicated at 33, and a line 34 (Figure 6) has been shown as passing through the point of contact of the disc with the abrasive and the axis of the disc 32.

Figure 6 is similar to Figure 5 but has been taken so as to look upwardly along a vertical plane containing the axis 32 of disc E in order to show the angularity that exists between the disc E and the abrasive at the point of contact. As seen in Figure 6, the plane of the disc makes an angle Z with the abrasive at the point of contact, and therefore abrasive contacting disc E is given an axial motion and upon being started on its course continues to move at down the abrasive incline until it is discharged from the rim of the wheel.

From the foregoing it is apparent that when the wheel is in operation disc E will undergo rotation in the direction indicated in Figures 5 and 6 through contact thereof with the abrasive, and the disc will dislodge a layer of abrasive from the body of abrasive lying in the rim of the wheel. In Figure 6 I have indicated by reference character 3'! the groove formed in abrasive remaining on the rim by the action of the disc in removing a layer of abrasive therefrom. However, groove 37 does not exactly show actual conditions because as soon as the abrasive lying on the rim is diminished in quantity, it is replenished by further abrasive passing through slots 2? in plate i 5, so that by the time the wheel makes a complete revolution the abrasive on the rim has again assumed substantially the form shown in Figure 1.

Although the disc E may cooperate with any desired portion of the abrasive lying on the rim it preferably is so related to the wheel as to dislodge the abrasive adjacent plate l5 rather than near the discharge edge. In Figures 5 and -6 I have shown the disc as cooperating with approximately the mid-portion of the abrasive lying on the supporting surface.

As seen in Figure 2, with the disc E disposed in an upward position, the abrasive discharges downwardly, although it may be caused to discharge in any desired direction by moving the axis of disc E in an are about the rotor axis in the proper direction to effect the desired direction of discharge. In View of the fact that the abrasive lying upon the supporting surfaces is rotating at exactly the speed of the rotor, when the abrasive is discharged, it will take a path almost exactly tangential to the rim of the rotor, especially in view of the fact that none of the parts of the apparatus acts upon the abrasive so as to give the final velocity a radial component.

In View of the fact that the abrasive in being discharged from the apparatus slides down the inclined surface of the abrasive, a slight axial component of velocity is imparted thereto and the conditions which bring this about are illustrated diagrammatically in Figure 6. With reference to Figurefi, the abrasive as it is dislodged by disc E takes a course approximately in accordance with line 38 and at the point of leaving the rim, it possesses a small axial componential velocity indicated by the vector Va, and it also possesses a tangential component of velocity indicated by the vector Vb, the latter being equal to the peripheral speed of the rotor at the point where the abrasive leaves it. The resultant of these two velocities is indicated by the vector VB in Figure 6.

Therefore, work to be cleaned of scale, molding sand or other surface accumulations may be rapidly cleaned by placing it in the path of dis charge of the wheel. If desired, the work may be moved under the wheel either by a conveyor, a tumbling barrel or the like, and the wheel caused to discharge down upon it as indicated in Figure 2. If desired, however, the wheel may be placed to one side of the work and disc E so adjusted as to cause the wheel to discharge sideways. On the other hand, if the work is to be passed over the wheel, disc E may be adjusted so as to cause the wheel to effect the discharge of the abrasive upwardly.

In Figures '7 to 16, inclusive, I have illustrated a further form of machine also embodying the invention, and with particular reference to Figures 7 and 14, the rotor embodies a web 6| having a plurality of rectangular openings s2 provided therein. The rotor is secured to a shaft by means of a plurality of screws it in a manner similar to the rotor of Figure 3 and it terminates at its periphery in a front flange id and a rear flange i5. Telescoped within flange i5 is an acceleration groove-forming ring it having a base portion 41 and an abrasive retaining flange 48. Disposed between base 3'! and web M is a ringlike spacer element 49 and a removable wear plate assembly 5i.

The entire assembly just described is secured in place on the rotor by means of a plurality of screws which pass through openings in the wear plate and the spacer and are threaded into the base portion of ring d6. Ring Mi cooperates with spacer 2-9 and wear plate assembly 5! to provide an inwardly facing abrasive-accelerating groove, and abrasive is fed thereto by a spout (Figure 8) 53 to which abrasive is supplied by gravity at a preferably metered rate of flow.

The lower end of the spout is provided with an offset portion 54 which conforms generally to the shape of the wheel and terminates slightly inside flange M. It is observed that the spout 53 is so inclined that abrasive dropping into the acceleration groove possesses an initial velocity and direction so as to reduce the shock or impact as the abrasive strikes the rotating mass of abrasive carried in the accelerating groove.

As seen in Figure '7 the abrasive wear plate assembly 5i is preferably made in four sections for ease of replacement, and each section is provided adjacent its periphery with a slot 55 through which screws 52 pass. Each plate 511 is also provided adjacent its periphery with a plurality of generally rectangular bosses 55, each of which is of a size slightly smaller than openings G2 in rotor web ll, so that when they are assembled in the wheel bosses 55 will fit into openings 52. At the lower end of each boss there is provided an abrasive slot 5'! through which the abrasive passes to the front of the wheel. The inner ends of plates 51 are secured in place on the rotor by a pair of semicircular plates 58, which are secured thereto by a plurality of screws (not shown).

It is, accordingly, apparent that rotor web ii, and also flange Q5, which are permanent parts of the machine are fully protected against the action of the abrasive. Bosses 5t fit into openings 22 and protect the walls thereof against wear, and spacer 49 and ring it protect the inner face of the flange against wear.

Referring now to the front flange shown in Figure 14, flange it is provided with an outwardly extending flange 59 which in turn is provided with an axially directed flange 6!. Flange 59 is also provided with an annular recess 62. Secured to flange 5% by a plurality of machine screws 63, which pass through openings therein, is an abrasive discharge ring 64. If desired, however, screws 63 may pass through openings in ring E i and be threaded into flange 59.

As seen in Figure 14, ring E l is so shaped as to conform to the meeting faces of flange 59 except that it is provided with an additional annular recess 65. Recess 65 cooperates with the rotor to provide a groove for the reception of rivet 23a of a flexible snap ring 22a which seats in a recess 65 provided in flange M and covers the inner surface of ring E l. This ring functions in a manner exactly similar to the ring 22 of Figure 3 and, accordingly, will not be further described. Ring 5% is provided with a conical discharge face 58 for a purpose that will presently appear.

I have shown a modified form of disc assembly for dislodging the abrasive from the rim of this form of wheel and it is shown more particularly in Figures 10, 11, 12 and 13. Referring to Figures 10 and 11, the wheel is provided with a housing having a flat side plate ll and it is provided with a large segment-shaped opening 12 through which the take-off disc assembly extends. The take-oif disc assembly is carried by a plate 13 which is mounted on the outside of side plate H for rocking movement about the axis of the rotor on a bolt and nut assembly i l, which may be tightened to securely clamp the parts after they have been properly adjusted. As seen more particularly in Figure 9, the upper or marginal edge of plate l3 is releasably clamped between the outside of side walls ii and a cover plate '15 which is secured to the side wall outwardly of the range of movement of plate 13 by means of bolt and nut assemblies iii.

Therefore, when base plate 13 has been moved into its proper adjusted position it may be securely clamped to plate H by tightening bolt and nut assemblies 16. Plate H is also provided with a slidable door if! (Figure 9), which may be opened to afford inspection of the machine while in operation.

Referring to Figures 10 and 11, plate 13 is provided with a pair of triangular-shaped side walls 11 and an end wall is. Walls ll project into the housing and define a pair of guideways 79. All of the parts of the disc assembly are supported on a sliding carriage or plate 8|, having four porjecting ears 82 whichcooperate with guideways E9. The opposite side of plate Bl as seen in Figure 13 is provided with four washerlike members 83 which are'secured thereto by cap screws 84. Members 82 and 83 cooperate with opposite sides of guideways l9 and mount plate ill for guided sliding movement in guideways 19.

Movement of carriage 3! is controlled by the mechanism shown in Figures 9 and 11, and it comprises a threaded member 86 which is nonrotatably secured in a lug 81 carried by plate 8 I, an" a nut assembly designated generally at 88 which is threaded on member and is provided with portions extending either side of a lug B9 secured to the face of base plate 13. The two parts of nut assembly 88 are rigidly secured together soas to lock plate BI against movement in either direction, and'it is,accordingly, seen that by inserting a tool in the openings 9'! provided therein, it may be rotated to cause threaded member 86 to move up or down, thereby effecting a similar movement-of carriage plate 3|. In order to prevent abrasive from working into the threads of member 86, I preferably provide a sealing. assembly 92 (Figure 9) between nutzSB and lug 81.

By rotating nut 88, the carriage plate may be moved up or down and as it moves substantially radially the disc'assembly may, accordingly, be moved toward and away from the rim of the wheel. In order to prevent lug 81 from restricting the angular adjustment of plate 13, plate 15 is provided'with a recess 90 for accommodating it.

Referring now to Figures 12 and 13, plate 8| is provided with a cylindrical opening 95 and extending therethrough is a head 96. The head 95 is provided with a clamping shoulder or face 91 abutting cooperation with the front face of plate 8|, and secured to the'rear of head Se by means of a plurality of cap screws 99 isa ring 98. The parts are preferebly so dimensioned that when screws 99 are pulled up tight, ring 98 will pull shoulder 91 of head 96 into clamping engagement with the front of plate BI, thereby locking the parts in fixed angular position.

Sleeve 96 is provided with a pair of aligned openings I I32 which register with a pair of hollow sleeves Hi3 secured to the outer face of member 96 by a welding operation or the like. J our naled in openings I02 are a pair of trunnion pins I04 which are threaded into a sleeve I65 which constitutes the support for the bearing assembly of the take-off disc shaft. Trunnion pins I04 are provided with screw driver slots I636 so that they may be firmly threaded home in the sleeve I05, and covering slots are a pair of discs I'Ill. Bearing against disc I01, for preventing endwise movement of trunnion pins H34 in their bearings, are a pair of screws I08 which in turn are threaded into cap members I 09 which are threaded into members I 03. A lock nut I III is employed to secure the parts after they have been properly adjusted. V

From the foregoing it is apparent that sleeve N15 is. journaled for rocking movement in member 96 and that if desired sleeve I55 may be moved transversely to its longitudinal axis by loosening locknuts H and rotating screws I 68 in the proper direction to effect the desired displacement. Locknuts II I] may then be tightened to securely lock the parts in the desired adjusted positions. This adjustment of the device increases or decreases the degree of offset S, previously discussed.

I have provided means for adjustably locking sleeve I65 in any desired position about the axis of trunnion pins I04, and it is most clearly shown in Figures 12 and 13. A pin I I2 is threaded into sleeve I and is disposed parallel to trunnion pins IM and lies in the same plane thereof. Pin I I2 extends freely through an externally threaded thimble H3, a lockwasher H4, and a nut II5. Thimble 3' extends through an arcuate, preferably graduated slot II' S formed in a bracket member I'I'I" secured to ring 98. In View of the fact that ring 98 is connected to member as by way of cap screws 99 it is apparent that pin II2 will always assume a fixed positionwith respect to head no matter what angular adjustment head '96 may assume with respect to plate BI.

Whenever it is desired to change the angle of inclination of the axis of the take-off disc with respect to the axis of the rotor, nut II 5 is loosened and the parts rocked into the desired position about the axis of trunnion pins I54. When the desired adjustment has been obtained, nut I I5 is tightened to securely lock the parts in place. In'view of the fact that pin II2 is freely slidable in thimble II3, it is. apparent that screws I58 may be adjusted to shift the axis of the disc transversely of its longitudinal axis without changing the angle of inclination thereof, as during this operation pin II2 merely slides within thimble II 3, maintaining the angle of inclination constant;

Mounted for sliding longitudinal movement within sleeve I 05 is a bearing sleeve I2I which is provided with an end cap I22 rigidly secured thereto. Rigidly anchored in cap. I22 is a stud member I23 and it extends loosely through an end'cap I 24 secured to sleeve I I35 by a plurality of cap screws I25. A nut I25 is threaded on stud I23 and by rotating it in the proper direction, sleeve I2I may be pulled to the right with respect to sleeve I05. In order to produce the opposite movement of sleeve I-2I, a bolt member I2! is threaded into cap I24 and bears against member I22 so that by rotating bolt IZ'I in the proper direction, sleeve I2I may be moved to the left with respect to sleeve I05. When the parts are in their desired adjusted position, screw I21 and nut I26 may be tightened so as to rigidly lock them in place. It is also apparent that by adjusting nut I26 and screw I21 the take-oil disc assembly may be moved toward or away from the rotor without varying the angle of inclination and without disturbing any of the other adjustments.

A conduit I29 is rigidly secured in an opening in cap I22 andis freely slidably associated with an opening in cap I24. Conduit I29 terminates in a lubricant fitting I3I (Figure 9) for connection to a grease .gun or the like for supplying lubricant to the interior of sleeve I2I for lubricating the bearings.

Mounted in sleeve I2I are a pair of anti-friction bearings I 32 and I33 and they are held in place by means of a sleeve I 3 8. Sleeve I34 is secured in position by means of a set screw I35 passing through an opening in sleeve I2I and threaded into sleeve I34. Mounted within bearings I32 and I33 is a shaft I35. Bearings I32 and I33 are spaced apart on shaft I36'by means of a spacing sleeve I31, and the entire assembly is secured in place thereon by means of a nut I38 threaded on a reduced end portion of the shaft.

It is to be understood that many of the features of the various forms of the changeable, and the appended claims are intended to embrace them in their several contemplated combinations. For instance, the various forms of discharge rim constructions may be used with the rotor shown in Figures 1 to 6, inclusive, as well as with the rotor of Figure 14. Also. the double take-off disc assembly of Figures 11, 12 and 13 may be used with the rotor of Figures l to 6, inclusive, instead of the single disc.

Shaft I 35 is provided at its outer end with a piloting surface I 39, upon which are mounted an inner disc MI, a spacer plate I42, and an outer disc I23. These parts are held in place on shaft I 39 by means of a plurality of cap screws I24,

which are threaded into a flange I45 provided on shaft I35. In order to prevent abrasive from finding its way into the bearing assembly, shaft i3 5 is preferably provided with a labyrinth joint with sleeve I2i, as indicated at M6, and also a rubber sealing member I4! is secured to a flange provided on shaft I36 by means of a wire M8 or the like.

The manner in which the take-off disc dislodges the abrasive from the rim of the wheel is substantially the same as that described in connection with Figures 5 and 6 of the drawings illustrating the first form of the invention. However, in view of the fact that two discs MI and i i?) are here employed, a greater volume of abrasive is dislodged at each revolution of the wheel and the angle of the discharge stream is greater than in the form of invention first described. Referring to Figure 16, I have somewhat diagrammatically illustrated the manner in which the discs cooperate with the body of abrasive. In this figure the body of abrasive is indicated by the reference character M9 and it will be observed that disc IdI dislodges a predetermined amount of abrasive or is embedded a predetermined distance in the body of abrasive, whereas disc Hi3, which slightly follows the scraping action of disc i ii (in point of rotation) is disposed to a greater depth in the body of abrasive and is hence of greater diameter. Although it is preferable to start with discs Hit and I43 of difierent diameters in order to provide vibrationless operation, they may, if desired, be of equal size as it has been found that they will Wear to the proper relative diameters after they have been in service.

It is, accordingly, apparent that in this form of the invention, Figures 7 to 16, inclusive, the abrasive is fed to the pick-up groove at the rear of the wheel, and through contact with the body of the abrasive lying in the groove, acquires within several revolutions, the full wheel velocity. fhe abrasive then flows from the pick-up groove, through the openings 51 in wear plate 5| and onto the front rim where it builds up to its angle of repose. Discs MI and I43 dislodge or scrape the abrasive from the rim, and as soon as it has been removed, it is immediately replaced by further abrasive flowing through openings 51. If desired, openings .i'l may be extended inwardly to a further distance, so as to allow the abrasive to flow freely therethrough without contacting their inner edges, thereby making for a greater inherent abrasive handling capacity of the wheel.

The stream discharged from this wheel is slightly different from that of the wheel previously described because of the conical discharge face 68, which imparts an axial velocity to the abrasive and causes the stream to spread out or be diffused axially and cover a greater area of the work.

It is also apparent that through the adjustments provided for the disc, the disc assembly may be moved toward and away from the rotor web without changing the angle of inclination thereof; the axis of the disc may be shifted transversely to increase or decrease the displacement S; the angle of inclination may be varied without changing any of the other adjustments, and also, by rotating nut member 86, the disc assembly may be moved bodily toward and away from the rim of the rotor so as to cause discs MI and H 53 to scrape a greater or less quantity of the abrasive from the layer of abrasive thereon. Also, when the discs have been worn at their outer edges through contact with the abrasive, nut 86 may be rotated to move the disc assembly bodily outward to compensate for the wear of the discs. Moreover, screws 99 may be loosened and head 96 rocked in carriage 8! for affecting further adjustment of the apparatus.

It has been found that a small quantity of abrasive will rebound out of the acceleration groove without going through the wheel, but this abrasive travels at low velocity and does no harm. However, a light housing (not shown) is preferably placed about the rear part of the rotor and is provided with a hopper bottom for feeding the abrasive back into the abrasive system.

The dimensions of the parts may assume any suitable values, but I have found that, in the wheel illustrated, a rotor having an inside diameter of approximately 29 inches when used with a pair of take-off discs having a diameter of approximately 10 inches will handle commercial quantities of abrasive and impart a velocity of approximately 200 feet per second to it when the wheel is rotated at approximately 2450 R. P. M. It is to be understood, however, that the invention is not limited to any particular dimensions, and they are merely given as illustrative of the concrete embodiment of the invention herein disclosed.

Referring now to Figures 1'? and 18 I have shown a modified form of discharge ring 64a which is adapted to be bolted to flange 59 of the rotor. This ring is used When it is desired to reduce the concentration of the abrasive stream or increase the width of the spray angle. Ring 64a is of waved shaped. configuration and is provided with a plurality of projections I5I which are highest at the periphery of the ring and decrease in height inwardly and finally merge with the surface of the ring at the inner edge of the ring.

During operation of the wheel, when provided with this ring, part of the discharged abrasive will pass between the adjacent projections I5! and thereby be delivered substantially in accordance with the diagram illustrated in Figure 6, whereas other particles of abrasive will strike projections I5! and be deflected axially, and it is apparent that the width of the abrasive stream is materially increased by the use of this ring.

In Figures 19 and 20 I have illustrated a further form of modified ring for application to the flange 59 of the rotor and it is employed when it is desired to impart a still higher velocity to the abrasive without increasing the speed of the rotor. Ring Mb is provided with a plurality of substantially radially extending blades I52 and they are provided with beveled inner edges I53.

Blades I52 extend closely adjacent the discharge edge of the rim, with the result that abrasive picked up thereby is subjected to practically no impact whatever as the difference in velocity is very slight. However, the blades are provided with beveled edges I53 in order to insure that the abrasive will be cleanly picked up by the blades and will not rebound off their inner edges in an axial direction. In order to further insure proper pick-up of the abrasive blades I52 are provided with beveled sides I56, and with reference to Figure 20 it is apparent that the bevel is such as to cleanly pick up the abrasive as it is discharged by the take-off disc. Ring Mb may be secured to flange 59 in any suitable manner, but I have illustrated the ring as provided with threaded openings I55 which terminate in low bosses I56 on the front face of the ring. Screws may be introduced through flange 59 and threaded in the ring for holding the ring on the rotor.

In view of the fact that the blades I52 are of appreciable radial length the abrasive will be given a further acceleration as it slides outwardly over the surfaces of the blades, and the abrasive discharged therefrom will have a higher velocity than when no blades are used. Also, the abrasive will leave the blades at an angle greater than a tangent in view of the fact that they possess a radial velocity in addition to the peripheral velocity of the rotor, and this is indicated by the vector diagram appearing in Figure 20.

In Figure 21 I have shown the rotor of Figure 14 as being equipped with a deflector ring assembly and this construction is used when it is desired to obtain a discharge that is concentrated in athin sheet adjacent the edge of the rotor. In this form of the invention the rotor is provided with a snap ring 2% carrying rivets 231) which seat in a groove in the rotor. Secured to flange 59, by means of shouldered space members I51 and bolt and nut assemblies I 58, is a deflector ring I59. With this device it is apparent that when the abrasive is discharged, if it has sufficient axial componential velocity it will strike ring I59 and be deflected back toward the rotor thereby tending to confine the abrasive discharge to a thin sheet.

In Figures 22' to 25, inclusive, I have illustrated a further embodiment of the invention wherein a rotor is used having an imperforate web, but it functions in the same general manner as the forms of invention previously described.

The rotor is provided with a web portion I 6! and a flange portion I62. Secured to flange portion I62, by means of a plurality of cap screws I63 or the like. is a rim member I64 and they preferably have a telescoping fit as indicated at I65. Although I have shown the rotor as comprising two separate parts, it is to be understood that the rotor may consist of an integral member if desired without departing from the spirit of the invention. The discharge end of flange IE4 is provided with a snap spring at 22, exactly in accordance with the first form of the invention and it cooperates with flange I65 in the same manner as ring 22 of Figure 3.

Removably secured to flange portion I62 by means of a plurality of cap screws I66 is a dam member I6! having a plurality of abrasive openings I68. The space between member I61 and the web of the rotor defines the abrasive acceleration or pick-up groove, and abrasive is supplied thereto in a manner similar to the rotor shown in Figure 14 by means of a conduit I69 having its discharge end located closely adjacent the body of abrasive in the groove and inclined so as to substantially tangentially deliver the abrasive thereto. The particular conduit shown has been illustrated in phantom lines because it is disposed forwardly of the section taken through the retor. In view of the fact that as the abrasive issuing from spout IE9 is apt to be ricocheted against the web of rotor I6! before it finally attains the peripheral speed of the abrasive lying in the groove I preferably provide a removable and replaceable wear ring III secured to the rotor by a plurality of screws I'IZ. As seen in Figure 22 plate III is located so as to lie in the region adjacent the level of the abrasive in the groove, indicated by the line I73.

' This form of the invention functions in the manner exactly similar to those previously described, the abrasive being picked up in the groove defined by plate I5? and the rotor web and feeding through openings I53 in plate I51 onto the rim of the rotor, from whence it is discharged by discs Id! and 543 as previously described. When openings I68 have become sumclently wornto require renewal of plate I6 3 the latter may be readily removed by removing cap screws I66 and sliding the ring out of the rotor. Also, when ring III requires replacement it may be similarly removed and replaced. It should be observed that neither of these operations require the dismantling of the machine and the machine accordingly must be out of service for only a very short time in order to completely renew the only wearing parts thereof.

In Figures 2a and 25 I have illustrated a modiiied form of abrasive dam and it assumes the form of a plate Idle having a plurality of sub stantially radial slots I '55 provided therein. They are preferably inclined with respect to the axis of the rotor as shown in order to increase the amount of abrasive that may flow therethrough. In view of the fact that this plate provides a very great flow of abrasive from the pick-up Zone to the discharge zone, it provides a much greater feeding capacity than the forms shown in Figures 22 and 23. Also, in view of the fact that the upper ends of slots I75 are entirely free, member liila does not limit the height to which the abrasive may build up on the rim, and therefore line IIfi, which indicates the level of the abrasive preferably assumes the angle of repose both in the acceleration groove and on the discharge rim, and the feed of abrasive is adjusted to almost exactly coincide with the rate at which the abrasive is removed from the rim, in order to prevent it from spilling out or being discharged at any point other than the discharge point as determined by the take-01f disc. It is observed that in both of the forms of the invention shown in Figures 22 to 25, inclusive, plates It? and Ifila perform the important function of insuring that the abrasive finding its way on the rim will be traveling at the full peripheral speed of the rim. This is brought about by reason of the fact that the abrasive must pass through openings I68 or slots I iii in order to find its way on the rim, whereas if the abrasive were allowed to travel directly from feed spout 613 to the discharge rim without passing through openings or slots, there is a possibility that it would feed onto the rim before reaching the full peripheral speed thereof.

As is well understood in the art, an unbalanced body rotating below a critical speed, and considering static balance only, will tend to rotate about its geometrical center whereas at speeds above the critical speed it will tend to rotate about its center of gravity.

Applying the above to all of the forms of wheels disclosed herein, it is apparent that if the wheel is properly balanced without any abrasive in it, the only thing that could cause an out of balance condition would be an uneven distribution of abrasive on the rim of the wheel. If abrasive is removed by a take-oil disc on the inside of the rim and the wheel is rotating at a speed below its critical speed so that it is rotating about its geometric center, the heavy side will swing out, pulling the light side in towards the center. In this case the disc will take ofi more abrasive from the lightly loaded side than it does from the heavily loaded side, thus aggravating the condition and increasing the unbalance. At

speeds above the critical speed the wheel will tend to rotate about its center of gravity so that the lightly loaded side will swing out, pulling the heavily loaded side towards the center. In this case the take-01f disc will take off more abrasive from the heavily loaded side than from the lighter side, thus continuously tending to keep the wheel in balance. The wheels are, accordingly, preferably operated at speeds above their critical speeds.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

I. In an abrading apparatus, a structure mounted for rotation at high speed in a predetermined direction about a fixed axis, said structure providing a generally annular surface facing toward the axis of rotation, means for depositing abrasive upon said surface while said structure is rotating, and at least one rotatable disc for engaging and dislodging abrasive from said surface at a predetermined point in the rotation of said structure, said disc being mounted for rotation about an axis disposed at an inclination with respect to the axis of said structure and being offset a predetermined distance forwardly with respect to the direction of rotation of said structure from a plane containing the axis of said structure, the axis of said disc lying in a plane disposed substantially parallel to said first named plane and intersecting said annular surface closely adjacent the region where said disc dislodges abrasive therefrom, the abrasive being operable to pile up on said annular surface and assume a predetermined angle -of repose thereon, and the axis of said disc being inclined to the axis of said structure at an angle substantially equal to the angle which the surface of said abrasive makes with the axis of said structure.

2. In an abrading apparatus, a hollow rotatable structure of generally disc-like form, said structure having a central, axially directed abrasive inlet opening, said structure terminating at its periphery in an inwardly facing generally annular abrasive supporting surface, means, rotatable synchronously with said hollow structure, for placing said abrasive inlet opening in communication with said abrasive supporting surface, and adapted to be maintained continuously filled with abrasive during operation of the apparatus, means for feeding abrasive into said inlet opening, and means for causing abrasive to be dislodged from said surface at one point in the rotation of said structure.

3. The abrading apparatus set forth in claim 2, wherein said structure is provided with a plurality of axially directed outlet openings adjacent said abrasive supporting surface for feeding abrasive thereto, said surface cooperating with said openings to maintain said hollow structure substantially full of abrasive during operation thereof.

4. In an abrading apparatus, a rotatable structure provided adjacent its periphery with an annular, inwardly facing abrasive receiving groove,

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means for depositing abrasive in said groove while said structure is rotating comprising a stationarily supported conveying means having a discharge portion located remote from the axis of said structure in close proximity to the normal abrasive level in said groove, said conveying means delivering a stream of abrasive to said groove over a fixed short are in the rotation of said structure, said structure also being provided with an abrasive supporting surface adjacent said groove and adapted to be supplied with abrasive therefrom, and means for dislodging a portion of the accumulated abrasive from said surface at a predetermined point in the rotation of said structure, said conveying means comprising a conduit the discharge portion of which inclines outwardly and forwardly with respect to the direction of rotation of said structure, for causing abrasive to be substantially tangentially deposited in said groove with an impact of minimum magnitude.

5. In an abrading apparatus, a rotatable structure, said structure comprising a disc-like web portion having adjacent its periphery on each face thereof an axially directed flange, one of said flanges terminating at its free edge in an inwardly directed ring portion which cooperates with said one flange and said web portion to define an abrasive receiving groove, stationarily supported means for supplying abrasive to said groove while said structure is rotating, said web portion being provided with a plurality of apertures through which abrasive may flow from said groove and be deposited upon said other flange, and control means for causing the deposited abrasive to discharge from said other flange at a predetermined point in the rotation of said head at an abrading velocity.

6. The abrading apparatus set forth in claim 5, together with a wear plate assembly disposed in said abrasive receiving groove and removably secured in surface engagement with the web portion of said structure for preventing abrasion thereof as abrasive is picked up in said groove.

'7. In an abrading apparatus, a rotor having a peripherally apertured web through which abrasive is adapted to flow, a wear plate secured in surface engagement with said web and having bosses fitting into the apertures in said web, said bosses protecting the walls 'of said apertures against abrasion and being provided with openings for permitting abrasive to flow therethrough.

3. In an abrading apparatus, a rotatable structure providing a generally annular surface facing toward the axis of rotation of said structure,

means for depositing abrasive upon said surface, and discharge means for disl'odging the deposited abrasive from said surface at a predetermined point in the rotation of said structure, said surface, adjacent the discharge portion thereof, being of generally cylindrical form, and a removable and replaceable wear ring secured in place on said surface.

9. The abrading apparatus set forth in claim 8, wherein said wear ring comprises a thin metallic split band and is resiliently sprung into place on said surface.

10. In an abrading apparatus, a rotatable structure providing an inwardly facing generally annular abrasive supporting surface, means for supplying said surface with abrasive while said structure is rotating; and means for dislodging the accumulated abrasive from said surface at a predetermined point in the rotation of said structure, comprising a pairof spaced discs mounted for rotation about a common axis which is offset and inclined withyrespect to the axis of rotation of said structure, said axis of said discs lying in a plane disposed substantially parallel to a plane containing the axis of said structure and intersecting said annular surface in the region where said abrasive is dislodged therefrom.

' 11. The abrading apparatus set forth in claim '10, wherein said discs are of different diameters and the said plane of the axis thereof is offset from the said plane of the axis of said structure forwardly with respect to the direction of rotation of said structure.

12. In an abrading apparatus, a rotatable structureproviding a generally annular inwardly facing abrasive supporting surface, means for supplying said surface with abrasive while said structure is rotating, and means for'dislodging a portion of the abrasive accumulated on said surface at a predetermined point in the rotation of said structure, said surface terminating in an edge over which the abrasive is discharged, said edge being of generally conical configuration for imparting an'a'xial component of velocity to said abrasive thereby causing the discharge stream to spread out overa considerable area.

13. In an abrading apparatus, a rotatable structure providing a generally annular inwardly facing abrasive sup'portingrsurface, means for supplying said surface with abrasive while said structure is rotating, and means for dislodging a portion'of the abrasive accumulated on said surface at ,apredetennined point in the rotation of said structure; said surface terminating in an edgeiover which the abrasive is discharged, said cdge' having a wave-shaped face for diffusing the abrasive discharging thereover, said face undulating peripherally so as to allow part of the abrasive to be directly discharged into space from said "abrasive supporting surface, and to causeipart of the abrasive to be deflectedaxially subsequent to discharge thereof from said abrasive supporting surface.

14. In an abrading apparatus, a rotatable structure providing a generally annular inwardly facing abrasive supporting surface, means for supplying saidsurface with abrasive while said structure is rotating, andmeans for dislodging a portion of the abrasive accumulated on said surfaceat a predetermined point in the rotation of said structure, said surface terminating in an edge over which the abrasive is discharged, and a ringin'ember secured to said structure adjacent to, but axially spaced from the discharge edge thereof, said ring member extending outwardly a considerable distance beyond said discharge dge'for controlling the degree of axial discharge "of abrasive from said structure.

15.'In' an abrading apparatus, in combination wit an abrasive propelling rotor having an inwardly' facing rim, a disc assembly for dislodging abrasive from the rim of said abrasive propelling rotor, comprising at least one disc mounted for rotation about an axis which is offset and inclined with respect to "the-axis of rotation of said rotor, and means for supporting said disc for adjustable rocking movement to vary the inclination of the axis'thereof with respect to the axis of said rotor, without varying the degree of oifset, for controlling the operating 1 characteristics of the apparatus.

16'. man abrading apparatus, in combination with *an abrasive propelling rotor having an inwardly facing rim, a disc assembly for dislodging abrasive from the rim of said abrasive propelling rotor, comprising at least one disc mounted for rotation about an axis which is offset and inadjusting movement to vary the degree of offset of the axis of said disc from the axis of said rotor without changing the degree of inclination thereof.

17. In an abrading apparatus, in combination with an abrasive propelling rotor having an inwardly facing rim, a disc assembly for dislodging abrasive from the rim of said abrasive propelling rotor, comprising at least one disc mounted for about an axis which is offset and inclined with respect to the axis of said rotor, and means for supporting said disc for bodily adjusting movement toward and away from the rim of clination thereof with respect to the axis of said r0 or.

with an abrasive propelling rotor having an inwardly facing rim, a disc assembly for dislodging abrasive from the rim of said abrasive propelling ing the degree of inclination thereof or the deree of offset with respect to the axis of said ro or.

20. In an abrading apparatus, a rotatable structure having a web portion provided adjacent said rotor. 21. In an abrading apparatus, a rotatable faces facing toward the axis of the rotor and disposed in side-by-side adjacent relationship; means for depositing abrasive upon one of said surfaces during rotation of said structure; said one surface having a mean diameter which is flow of abrasive from said one surface to said other surface; and means for dislodging a portion of the abrasive accumulated on said other surface at a predetermined point in the rotation of said structure.

22. The abrading apparatus defined in claim 21, wherein said one surface is of generally frustro-conical shape and inclines outwardly toward said other surface.

23. The abrading apparatus defined in claim 21, wherein said means for controlling the flow of abrasive comprises a ring-like member separating said surfaces and having a plurality of openings provided therein.

24. In .an abrading apparatus, a rotatable structure having an outwardly extending web portion, said web portion being provided adjacent its periphery with an axially directed flange assembly, said flange assembly providing an annular abrasive supporting surface terminating at its free end in a discharge edge and having an annular abrasive receiving surface disposed between said web portion and said abrasive supporting surface, stationarily supported abrasive conveying means for depositing abrasive upon said receiving surface while said structure is rotating, said conveying means having a discharge portion terminating close proximity to, but spaced from said receiving surface, said receiving surface being operable to feed abrasive to said abrasive supporting surface, and a ring-like member secured to and rotatable with said structure and being located inwardly of said flange assembly between said abrasive supporting surface and said receiving surface, said ring-like member having :a plurality of openings therein through which abrasive is adapted to be fed in predetermined quantities to said abrasive supporting surface; and means for dislodging a portion of the abrasive accumulated upon said abrasive supporting sursurface at a predetermined point in the rotation of said structure.

25. In an abrading apparatus, a rotatable structure having a generally annular surface facing toward the axis of rotation and a generally circular -element dividing said annular surface into an abrasive receiving surface upon which the abrasive is adapted to be accelerated, and an abrasive supporting surface from which the abrasive is adapted to be discharged; feeding means for delivering a stream of abrasive upon said abrasive receiving surface while said structure is rotating; said generally circular element having a plurality of openings for feeding abrasive from said abrasive receiving surface to said abrasive supporting surface; and means for dislodging a portion of the accumulated abrasive from said abrasive supporting surface at a predetermined point in the rotation of said structure.

26. The abrading apparatus defined in claim 25, together with a second generally circular element cooperating with said first generally circular element and said abrasive receiving surface to provide a comparatively deep groove in which a body of abrasive is adapted. to be centrifugally retained during rotation of said structure.

27. In an abrading apparatus, a rotatable structure comprising a supporting web termicircular member cooperating with said web and flange to provide'a groove in which abrasive is adapted to be acceleratedxa feed conduit having a discharge portion located adjacent said groove for delivering abrasive thereto; a circular disc-like wear plate detachably secured to said web adjacent the region where said feed conduit discharges into said groove, for protecting said web against abrasion, said circular member embodying passage means for feeding abrasive from said groove to said flange; and means for dislodging a portion of the abrasive accumulated on the latter at a predetermined point in the rotation of said structure.

28. The abrading apparatus defined in claim 2'7, wherein said flange includes a replaceable wear ring disposed adjacent the free edge thereof, and from which said abrasive is discharged from said structure.

29. In an abrading apparatus, a rotor having a generally annular surface facing toward its axis of rotation; means for delivering abrasive nating at its periphery in a substantially annular flange facing toward the axis of rotation; a

to said surface; and a rotatable member for dislodging a portion of the accumulated abrasive, mounted for rotation about an axis, said member being so disposed that a line normal to its aXis and passing through the point on its periphery furtherest from the axis of rotation of said rotor, intersects a line normal to the axis of said rotor and passing through said point.

30. The apparatus defined in claifn 29, wherein the axes of said rotor and member are located in a pair of spaced parallel planes, and the axis of said member is offset forwardly from the plane of said rotor axis with respect to the direction of rotation of said rotor.

31. An abrading apparatus comprising a rotor having an internal annular abrasive supporting surface, means for delivering abrasive to said rotor for deposit upon said surface during rotation thereof, a rotatable disc for engaging and dislodging a portion of the deposited abrasive from the rotor, and means mounting the disc for rotation about an axis which lies in a plane which is spaced from and parallel to a plane containing the rotor axis, and so that a radial line of the rotor passing through the center of the disc makes an acute angle with respect to said plane containing the rotor axis.

32. In an abrading apparatus, a rotatable structure including a hollow member providing on its interior and outermost from the axis of rotation of the structure a pair of generally annular surfaces facing towards the axis of the rotor, one of said surfaces having a mean diameter which is substantially less than the mean diameter of said other surface, and said surfaces being so adjacent and side by side with respect to each other that abrasive upon the surface of smaller diameter will feed in one general direction directly over and upon the surface of larger diameter, means disposed between the surfaces for controlling the fiow of abrasive from the smaller to the larger one of them, means for depositing abrasive upon the smaller of said surfaces during rotation of said structure, and means for dislodging a portion of the abrasive accumulated on the larger of said surfaces at a predetermined point in the rotation of said structure.

GARRETT B. LINDERMAN, JR. 

